MRI Phase Correction via Weighted Common Value
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Solution Overview
Problem
Current techniques for combining Echo Planar Imaging (EPI) and Parallel Imaging (PI) in MRI struggle with accurate phase correction, leading to folded artifacts due to differences in signal noise ratio (SNR) among receiving coils, which affects image quality and positional shifts.
Innovation Solution
A method is introduced to calculate a common phase correction value using pre-scan data from each channel, combining phase differences with weighted averaging based on signal values, avoiding the need for individual channel corrections and preventing folded artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If phase correction is performed by calculating a phase correction coefficient for each receiving coil channel, then phase correction can be applied to each channel individually, but errors occur in the phase correction amount due to differences in SNR among channels, causing folded artifacts in the combined image
Solution Approach 1:
The patent merges the phase correction process by calculating a single common phase correction value from pre-scan data of all channels and applying it uniformly to all channels during image formation, instead of calculating separate phase correction coefficients for each channel. This combining approach eliminates errors caused by SNR differences among channels and prevents folded artifacts in the combined image.
2Measurement precision
If a phase correction coefficient is calculated from pre-scan data of each channel, then individual channel phase errors can be corrected, but the calculation becomes complex and folded artifacts still occur due to channel combination issues
Solution Approach 1:
The patent simplifies the phase correction process by merging all channel pre-scan data to calculate a single common phase correction value, rather than performing separate calculations for each channel. This reduces computational complexity while maintaining correction effectiveness across all channels through the unified common value.
3Measurement precision
If individual channel phase correction is performed, then each channel's phase error can be addressed, but shifted artifacts occur in the combined image due to misalignment between sensitivity distribution and phase-corrected data
Solution Approach 1:
The patent eliminates shifted and folded artifacts by merging all channel data to compute a common phase correction value that is applied uniformly across channels. This unified approach ensures proper alignment between sensitivity distribution and phase-corrected data during channel combination, preventing the occurrence of shifted artifacts in the final combined image.
Data Source
AI summary
To provide a technique in which, in imaging using an EPI method, an occurrence of an artifact when phase correction is performed for each channel is avoided and the phase correction is accurately performed. A common phase correction value to be applied to data of all channels is calculated using pre-scan data of each channel. The common phase correction value is obtained by combining a difference phase obtained for each of the channels. The difference phase is obtained by complex integration, while an absolute value of each channel is maintained as it is. The combination is performed by complex average, and averaging processing according to a weight of the absolute value is performed. The occurrence of an artifact can be prevented by using the common phase correction value, and robust phase correction can be performed by including the weight of the absolute value.